1. Field of the Invention
The present invention relates to button switch devices equipped with display portions that are illuminated.
2. Description of the Related Art
Japanese Utility Model Laid-Open No. 6-50191 discloses a button switch. The button switch has two light sources, and the display state of the button is changed by switching the illumination states of the light sources. In this button switch, a pressing rod formed behind a pressing surface of the button switch is used to press down the top portion of a push switch to turn on the switch. In addition, in order to illuminate individual display portions with only light emitted from the corresponding light sources, a light shielding wall is formed between the two light sources.
However, the device structure of the push button disclosed in Japanese Utility Model Laid-Open No. 6-50191 is not desirably reliable. An operator will not necessarily press the center of the push button. Sometimes an off-center position of the push button is pressed. In particular, when a display on the button is changed, the operator tends to press a position where the display appears (off-center position). When the button is pressed at an off-center position, the entire push button is inclined, and accordingly, the pressing rod is also inclined. This prevents the push button from being pressed down in a direction perpendicular to the switch. For this reason, a possibility of a switch input being defective increases. In the device disclosed in Japanese Utility Model Laid-Open No. 6-50191, restoration force after the push button has been pressed down is only derived from the elastic force of the push switch. When the push button is significantly inclined and the pressing rod is moved out of the top portion of the switch, switch input is disabled and the button having been pushed down does not return to the state that existed before the button was pressed down. In addition, with regard to restoration force, the device depends on the elastic force of the push switch. For this reason, a sufficient restoration force is not obtained, or a sensation of a smooth pressing operation is not easily obtained.